Captain Davis added: “We are capable of defending against a North Korean ballistic missile attack and will take all necessary measures to deter and defeat threats to our and our allies’ territories and citizens.”

On Sunday, North Korea said it had successfully test-fired a new type of medium-to-long range ballistic missile.

In violation of United Nations resolutions, the hermit nation fired a medium to long range ballistic missile and according to state-run news agency KCNA, the weapon is capable of carrying a nuclear warhead.

America and South Korea prepare for war against North Korea Tue, January 24, 2017

U.S. and South Korean marines participate in the endurance exercise in temperature below minus 20 degrees celsius under a scenario to defend the country from any possible attacks from North Korea.

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But according to the spokesman, US defence officials are particularly concerned that it appears to be propelled by solid fuel and fired from a mobile launcher.

Captain Davis added: “This is one of the concerns we've had, as they have developed their capability in the missiles themselves, they have also given them a road mobile capability.

“Road mobile allows it to hide, to evade detection and to be able to launch with little notice.”